diff --git a/src/__tests__/unit/chat-resources.test.ts b/src/__tests__/unit/chat-resources.test.ts
index 0f2968d..f866baf 100644
--- a/src/__tests__/unit/chat-resources.test.ts
+++ b/src/__tests__/unit/chat-resources.test.ts
@@ -94,6 +94,7 @@ describe('Chat resource', () => {
       messages,
       model: 'gpt-4',
       stream: false,
+      safety_identifier: 'oai-guardrails-ts',
     });
     expect(client.handleLlmResponse).toHaveBeenCalledWith(
       { id: 'chat-response' },
@@ -153,6 +154,7 @@ describe('Responses resource', () => {
       model: 'gpt-4o',
       stream: false,
       tools: undefined,
+      safety_identifier: 'oai-guardrails-ts',
     });
     expect(client.handleLlmResponse).toHaveBeenCalledWith(
       { id: 'responses-api' },
diff --git a/src/resources/chat/chat.ts b/src/resources/chat/chat.ts
index f859484..7be01b6 100644
--- a/src/resources/chat/chat.ts
+++ b/src/resources/chat/chat.ts
@@ -89,6 +89,8 @@ export class ChatCompletions {
         model,
         stream,
         ...kwargs,
+        // @ts-ignore - safety_identifier is not defined in OpenAI types yet
+        safety_identifier: 'oai-guardrails-ts',
       }),
     ]);
 
diff --git a/src/resources/responses/responses.ts b/src/resources/responses/responses.ts
index 0441af4..468e4e5 100644
--- a/src/resources/responses/responses.ts
+++ b/src/resources/responses/responses.ts
@@ -85,6 +85,8 @@ export class Responses {
         stream,
         tools,
         ...kwargs,
+        // @ts-ignore - safety_identifier is not defined in OpenAI types yet
+        safety_identifier: 'oai-guardrails-ts',
       }),
     ]);